The present invention relates generally to the interfacing with computer and mechanical devices by a user, and more particularly to devices used to interface with computer systems and telemanipulator devices and which provide haptic feedback to the user.
Humans interface with electronic and mechanical devices in a variety of applications, and the need for a more natural, easy-to-use, and informative interface is a constant concern. In the context of the present invention, humans interface with computer devices for a variety of applications. One such application is the control of telemanipulator devices to interface with physical environments. Other applications include interacting directly with computer-generated environments such as simulations, games, and application programs.
Telemanipulator devices are often used for remote manipulation of physical objects and items in areas that can be difficult or unavailable for humans to operate directly. For example, telemanipulator devices can be used in hazardous environments, such as radioactive areas or extremely hot areas, to manipulate items in that environment. Other areas where these devices are commonly used include underwater or the ocean, outer space, areas having poisonous gasses in the air, etc. With these devices, exploration of an environment, retrieval of samples from the environment, or operation and maintenance of equipment within the environment can be performed with little risk to humans.
A typical telemanipulator includes a master end effector (or "master") and a slave unit (or "slave"). An operator or user manipulates the master device in provided degrees of freedom, control signals are transmitted from the master to the slave, and the slave is moved and manipulated in a fashion corresponding to the manipulation of the master. In some telemanipulator devices, the slave sends back information to the master indicating a present state of the slave or providing information about the slave's environment. The slave is commonly a robot arm having one or more instruments or devices attached to the arm. For example, a parallel jaw gripper can be attached to the robot arm and moved within the slave's environment to grasp, pick up, and move objects. Alternatively, or additionally, the slave end effector can include a camera, light source, welding torch, wrench, screwdriver, cutting blade, or other instrument. The slave can be mounted on a static surface, or can be placed on a mobile entity such as a vehicle that can be, for example, piloted using remote control. A computer is preferably used to interface the master with the slave, to provide appropriate signals in bi-directional communication, and perform processing of signals or automated control of the slave when necessary.
The master end effector can take a variety of forms. One configuration uses a joystick-like controller to manipulate the slave. The operator moves the joystick handle in two or more degrees of freedom, which moves designated portions of the slave in corresponding degrees of freedom. One problem with joystick master controllers is that the control of the slave is not very intuitive, and achieving proficiency with this type of master requires considerable operator training. Other master end effectors are more intuitive for the operator. Exoskeletons or linkages can allow an operator to make movements with the master that cause closely-corresponding movements of the slave. For example, a grip can be attached to a linkage having six degrees of freedom, and the grip can be moved and rotated in space in a fashion that the operator wishes the instrument on the slave to move and rotate.
In some telemanipulator devices, force feedback or tactile feedback is also provided to the user, more generally known herein as "haptic feedback." These types of telemanipulator devices can provide physical sensations to the user manipulating the master end effector. When the slave impacts a surface or other obstruction, or otherwise interacts with its environment, it is desirable that the operator sense this interaction. Thus, forces provided on the master end effector can help the operator guide and operate the slave more effectively. If the slave impacts a wall, a force corresponding to what the slave experiences can be output on the master end effector using motors or other actuators of the master device.
One problem with haptic feedback used in master end effectors of the prior art is that the haptic feedback provided to the operator concerning the interactions of the slave with its environment is very limited and/or not well correlated to fine control of the slave, so that the operator receives only a crude sense of what is happening in the slave environment. For example, higher frequency tactile cues such as occurs when two hard objects contact each other are omitted. Furthermore, for slave devices having a jaw gripper, there is no haptic feedback provided to the operator concerning the movement and interaction of the jaw gripper with other objects. In addition, current equipment for teleoperation can be expensive and often has reliability and stability problems in harsh environments such as underwater oil rig maintenance.
Another problem is the degree of control provided to the operator over the slave device. Master control over such slave instruments as a gripper is often crudely performed with devices such as buttons and triggers, which do not greatly help the operator manipulate the gripper to perform highly delicate operations, and do not provide an intuitive control mechanism.
In other interface applications, the user interacts not with a physical environment, but with a computer generated or virtual environment. For example, in virtual reality applications or computer games, an interface device is coupled to a host computer which is running an application program that provides an environment, such as a graphical environment. The computer generated environment is displayed on a device such as a computer display. The user manipulates controls such as a manipulandum joystick handle, mouse, etc.), buttons, switches, or the like, and sensors detect the manipulation and input signals to the host computer to allow corresponding manipulation of graphical objects displayed on a display screen. Haptic feedback can be added to such interface control devices to provide the user with a more interactive experience and to provide greater ease in interfacing and controlling computer-generated objects and environments. A problem with current haptic feedback devices, however, is that the haptic feedback is not very well integrated into some types of controllers, such as gamepads or other controllers besides traditional joysticks.